The present specification relates generally to a weather radar system. More particularly, the present specification relates to beams or beam patterns for detecting a weather phenomenon.
U.S. Pat. No. 5,311,183 discloses an aircraft weather radar system. Conventional aircraft weather radar systems are capable of scanning for certain weather phenomena, such as wind shear, turbulence or micro-burst situations. U.S. Pat. No. 6,388,608 assigned to the assignee of the present application and incorporated herein by reference discloses a weather radar system with wind shear detection capabilities. U.S. Pat. No. 6,388,608 discloses an embodiment that detects turbulence, micro-bursts or wind shear by scanning at two or more tilt angles using a radar antenna and determining wind speeds at various elevations. Windshear, turbulence or micro-burst warnings are generally desirable when the airplane is in the landing, taxi and take-off modes.
Reducing antenna size on weather radar systems is desirous, especially on smaller aircraft (e.g., business and regional jets). Larger antenna size adds to the size drag and/or weight of the aircraft. However, the wider radar beam associated with a smaller antenna increases the probability of false alarms during weather phenomenon detection, such as, wind shear, turbulence and/or micro-burst detection. The false alarms can be due to ground clutter targets and targets outside of the flight path of the aircraft.
Accordingly, there is a need for a scanning strategy for detecting weather phenomena, such as wind shear, microburst and/or turbulence that is less susceptible to false alarms. There is also a need for a radar system that intermixes radar beams with independent pointing angles or beam shapes to obtain returns for predicting wind shear. There is also a need for a radar system and process that takes advantage of all or some possible transmitter and receiver sampling times to implement beam diversity and increase robustness of wind shear detection. Further, there is a need for a cost effective robust wind shear detection system for use with smaller antennas, such as electronically scanned antennas selectable subaperture antennas. Yet further, another need exists for a system and method of hazard detection with minimal false alarms while using a small antenna.